Mechanically actuated hammer and bit assembly therefor

ABSTRACT

A percussion bit assembly for use with a mechanically actuated hammer, and of a mechanically actuated hammer including the above-mentioned percussion bit assembly and an exemplary actuator. The percussion bit assembly is constructed to include a percussion bit and a plurality of toroidal springs mounted to provide lateral reactive forces in response to lateral movement of the percussion bit. A brake structure is also included which directly engages the percussion bit.

United States Patent 11 1 1111 3,881,554

Cooley et al. 1 May 6, 1975 [54] MECHANICALLY ACTUATED HAMMER 2,177,935 10/l939 Buck l73/l27 X AND BIT ASSEMBLY THEREFOR 3,566,978 l/l969 .t l73/l39 3,605,916 9/1971 173/139 [76] in ntors: ill C. y, 5400 Pooks Hlll 3,687,008 8/1972 Densmore 91/276 Rd. Bethesda, Md. 20014; Franklin 3040 39th Primary Examiner-Frank L. Abbott washmgton 20016 Assistant ExaminerWilliam F. Pate, Ill [22] Fil d; M 25, 1973 Attorney, Agent, or Firm-Edwin E. Greigg [2|] Appl. No.: 363,879

[57] ABSTRACT 52 s CL H 173 13; 191 27 173/ 9; A percussion bit assembly for use with a mechanically 173/127; 173N139; M31162 actuated hammer, and of a mechanically actuated [51] int. Cl B25d 9/04 hammer including the above'memioned Pemussion bit 158 Field of Search 173/13, 119, 127. 139. assembly and an exemplary actuator The Percussion z 9 H4 5, 92 bit assembly is constructed to include a percussion bit 4O4I|332 299/691 7 74/132, 379 R and a plurality of toroidal springs mounted to provide lateral reactive forces in response to lateral movement 5 References Cited of the percussion bit. A brake structure is also in- UNITED STATES PATENTS cluded which directly engages the percussion bit.

2.024,684 l2/l935 Erfass 173/156 UX 22 Claims, 3 Drawing Figures 1 14 RESERVOIR PUMP m 7a 1 2a 22 24 22 24 2a 104 22 94 102 m as as 82 gglal as so 20 $0 1 mt 32 2e t\ I22 72 ET: 1) 1 14 1 3%:

84 62 a 2 0 lo '2 9a 58 54 m 0 34 36 32 $0 Q4 52 Z2 2 RETURN VALVE T0 PUMP 116 MECHANICALLY ACTUATED HAMMER AND BIT ASSEMBLY THEREFOR CROSS REFERENCE TO RELATED APPLICATION The present application discloses subject matter common to applicants concurrently filed copending application Ser. No. 363,878 entitled Hydraulically Powered Actuator."

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the field of mechanically actuated hammers, and more particularly to a unique mechanically actuated hammer and to a percussion bit assembly for use with a mechanically actuated hammer.

2. Description of the Prior Art Hammers known heretofore, which are used, for example, for tunneling, mining, quarrying and general demolition work, have been found unsatisfactory because they are unable to deliver a blow energy output in excess of approximately 3,000 FT-LBS. Hammers of higher energy are generally subject to mechanical damage or are inefficient and unreliable in operation.

One known device of high energy is disclosed, for example, in U.S. Pat. No. 3,605,916, issued on Sept. 20, 1971 to B. V. Voitsekhovsky et al. The device disclosed in this patent is limited in efficiency, inter alia, by the fact that liquid is throttled through narrow radial ports which causes the moving ram element of the actuator to be subjected to excessive liquid drag.

Also worthy of note in the field of percussive-type hammers, that is, hammers in which the primary moving ram element directly accelerates a bit which, in turn, strikes a work surface, are certain energy limiting factors, such as for example, the strength and resilience of the mechanical structure.

The large hammer developed by B. V. Voitsekhovsky et al is capable of a blow energy of 70,000 ft. lbs. However, in addition to the disadvantage pointed out above, it is expensive, quite complicated in construction, and subject to wear and gas leakage from the compressed gas springs which support the bit laterally.

It would therefore be desirable to have a hammer which effectively overcomes the problem of liquid drag, is relatively inexpensive, less complicated in construction and reliable even in those situations where lateral skidding occurs and which possesses a capability of delivering greater than 3.000 FT-LBS of energy per blow. In conjunction with this goal it would also be desirable to have a hammer which includes an efficient and effective braking system which affords protection to the hammer in the event that the bit fails to strike its target, or strikes a target which permits free entry.

OBJECTS AND SUMMARY OF THE INVENTION It is, therefore, a general object of the present invention to overcome the stated disadvantages of the known prior art.

It is a more specific object of the present invention to provide a percussion bit assembly which is simple in construction, reliable in operation and inexpensive to fabricate.

It is another object of the present invention to provide a percussion bit assembly for use with a unique mechanical impulsetypc actuator.

It is still another object of the present invention to produce a percussion bit assembly for use with any of the known actuators comprising the present state of the art.

It is yet another object of the present invention to provide a percussion bit assembly which includes a compressed gas spring system capable of exerting both lateral and axial reactive forces.

It is still another object of the present invention to provide a percussion bit assembly which utilizes inexpensive and available components, such as rubber tires, for use as a component part of a spring system capable of exerting both lateral and axial reactive forces.

It is yet another object of the present invention to provide a percussion bit assembly which includes a brake system which is directly applied against the percussion bit to thereby safely and reliably brake the percussion bit in the event that the bit fails to strike its intended target.

It is a related object of the present invention to provide a mechanically actuated hammer in which high output energies are achieved by a unique structure for liquid escape.

It is another related object of the present invention to provide a mechanically actuated hammer including a mechanical impulse actuator with a displaceable cylinder which serves as a working cylinder in conjunction with a piston assembly.

These and other objects are accomplished according to the present invention by the provision of a percussion bit assembly which includes a housing, a guide means for axially guiding the percussion bit during its axial displacement, spring means mounted between the guide means and the housing which are capable of exerting lateral reactive forces in response to the lateral displacements of the percussion bit, and brake means mounted to directly engage the percussion bit in order to decelerate the axial movement of the percussion bit and thereby limit the stroke of the actuator.

Moreover, there is provided a mechanically actuated hammer including the percussion bit assembly set forth above and any known actuator, or a mechanical impulse-type actuator which includes a piston assembly, which produces a reciprocating output, and a cylinder within which the piston assembly is reciprocated, and which is itself displaceably mounted in order to provide a large passage for liquid escape during firing of the piston assembly.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view in cross section illustrating a hammer according to the present invention which includes a percussion bit assembly having novel spring and brake means, and a novel mechanical impulse actuator.

FIG. 2 is a schematic view in cross section illustrating an alternative embodiment of the braking system according to the invention.

FIG. 3 is a schematic view in cross section illustrating the novel mechanical impulse actuator according to the present invention including specifics of an alternate embodiment of an associated control circuit for the actuator.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Turning now to a more detailed consideration of the present invention as illustrated in the exemplary embodiments of FIGS. 1-3, there is shown a mechanically actuated hammer comprising a percussion bit assembly l2 and a hydraulic actuator assembly 14.

It should be understood at the outset that the percussion bit assembly 12, although illustrated in combination with a particular hydraulic actuator assembly 14. can be combined with other and different actuator assemblies known in the art and still achieve its intended objects.

The percussion bit assembly 12 is constructed to include an outer generally cylindrical housing 16 which can be connected in any conventional manner, for example, by welding, to the actuator assembly l4. Within the outer housing 16 there is provided a percussion bit 18 along with supporting structure for supporting the percussion bit 18 to the housing 16, and flexible or articulated connecting structure for connecting the percussion bit 18 to the reciprocating output of the actuator assembly 14.

The supporting structure comprises a generally cylindrical guide tube 20 within which the percussion bit 18 is axially and rotationally displaceable. The guide tube 20 is, in turn, mounted to the housing 16 by a spring system preferably formed of a plurality of flexible toroidal members 22, such as, for example, conventional pneumatic tires utilized on vehicles. Preferably two sets of toroidal members 22 are provided as shown in FIG. l. However, it should be understood that any desired number of these members or sets of members can be employed. The toroidal members 22 forming the spring system, which can be pressurized in any known manner, are mounted between the guide tube 20 and the outer housing 16 in such a way that they are capable of exerting both axial and lateral reactive forces on the guide tube 20 in response to axial and lateral displacements of the guide tube 20 caused by impact motions of the percussion bit 18. To achieve this result, the individual toroidal members are mounted in facing recesses 24 and 26. These recesses are formed by spaced annu lar members in the form of rings 28. A first portion of the rings 28 form with the outer surface of the guide tube 20 a plurality of first recesses, while the second portion of the rings 28 forms with the inner surface of the housing 16 a plurality of second recesses. Between respective facing recesses, the individual toroidal members are mounted. The rings 28 may be formed integrally with the housing 16 and the guide tube 20, or they may be formed separately and connected to the housing 16 and guide tube 20 in a conventional manner.

The radial extent of the rings 28 is sufficient to establish a sufficient reactive surface area with the toroidal member being mounted. it should also be noted that the spacing between adjacent rings 28 between which the open ends of the toroidal members 22 are mounted, that is, the bead ends in the case of pneumatic tires, are sufficiently spaced in the axial direction of movement of the percussion bit 18 to ensure an adequate seal for retaining the pressurized medium within the toroidal members from escaping under load. It can be seen that as a result of the spring system according to the present invention, an effective and yet inexpensive means is provided for controlling both lateral and undesirable axial excursions of the guide tube 20 after impact of the percussion bit 18, while limiting the magnitude of maximum force applied to the structure 16, and protecting the actuator 14 from damage.

The spring system is capable of exerting higher reactive loads than any of the known systems by reason of the fact that the reactive surface areas are annular. There is, therefore, a greater reactive surface area available according to the spring system of the present invention. By increasing the number of toroidal springs and/or increasing their internal pressure, the lateral spring force can be increased as desired.

Mounted to the inside surface of the guide tube 20 in the vicinity ofits two extremities are guide bushings 30. The guide bushings 30 are retained in position, according to the preferred embodiment illustrated in FIG. 1, by end rings 32. Of course, the guide bushings 30 could alternatively be made integral with the guide tube 20, or retained in position by means other than the end rings 32.

According to one preferred embodiment of the present invention, there is provided a brake system for braking the percussion bit 18 if it exceeds a predetermined axial displacement. The brake system illustrated in FIG. 1 includes a brake shoe support tube 34 which is mounted to the inner surface of the guide tube 20 approximately midway between the two guide bushings 30. The brake shoe support tube 34 is mounted to the guide tube in any conventional manner, as for example, by bolts 36. Extending from the inner surface of the brake shoe support tube 34 is a brake shoe 38. The brake shoe 38 is mounted to the brake shoe support tube 34 in any conventional manner. It should also be noted that the support tube 34 can be formed of segmented members, and that the brake shoe 38 can also be a single annular member or a plurality of segmented members. ln addition, it should also be noted that the location of the brake system 34-38 between the guide bushings 30 is arbitrary, depending upon the desired stroke limitations of the percussion bit 18.

The percussion bit 18 includes a portion 18d having a tapered surface which engages a correspondingly tapered surface 40 of the brake shoe 38 after a predetermined axial displacement of the percussion bit 18. This engagement gives rise to a braking force applied directly to the percussion bit IS in association with concurrently applied axial reactive forces in the spring system. This reactive loading effects a deceleration of the axial movement of the percussion bit which thereby limits the stroke of the actuator.

Like the spring system, the brake system is also quite reliable and inexpensive. Heretofore, so far as applicants are aware, braking systems which effect axial deceleration of the percussion bit assembly or the equivalents of such a braking system, are usually located in the actuator assembly [4. These systems are much more complex and more difficult to service than the system according to the present invention.

An alternative braking system is illustrated in FIG. 2. According to this embodiment, the guide tube 20 is mounted to be axially displaceable with the percussion bit 19 after a predetermined axial displacement of the bit 18. Preferably, according to this embodiment, brake shoes 38 are mounted both to the guide tube 20 and the outer surface of the individual toroidal members 22. The guide tube 20 includes a tapered portion 42 at one end thereof, to the inner surface of which a brake shoe 38 is secured in a conventional manner. In this case the brake shoe 38 of the guide tube 20 has a conical internal surface which is engaged by the tapered portion 18d of the percussion bit 18 near the end of its motion.

The individual toroidal members 22 are mounted to the outer surface of the guide tube 20 by the annular rings 28. Support rings 44 are fastened to the closed ends of the toroidal members 22 in a conventional manner. To the rings 44 there are mounted brake shoes 38 which directly engage the inner surface of the outer housing 16. in the event that the percussion bit 18 is displaced in the axial direction beyond a predetermined distance, the tapered surface portion 18d is brought into engagement with the brake shoe 38 which, in turn, causes the guide tube 20 to be displaced in the axial direction with the percussion bit 18. This causes the brake shoes 38 mounted to the support rings 44 to generate frictional force axially on the inner surface of the outer housing 16. The frictional engagement of the brake shoes 38 with the inner surface of the outer housing 16 effects deceleration of the percussion bit 18, which thereby limits the stroke of the actuator.

To return the guide tube 20 to its initial position, the percussion bit 18 is provided with a ring 46 formed near its tip end. The ring 46 engages the flange 48 formed at one end of the guide tube 20 and retracts the guide tube 20 during cocking of the percussion bit 18 by the actuator. it should also be noted that each brake shoe 38, according to the embodiment illustrated in FIG. 2, may be formed as a continuous annular shoe or as a plurality of segmented shoes.

Returning to FIG. 1, it can be seen that the percussion bit 18 is formed as an elongated generally cylindrical shaft member having a work-engaging conical tip portion 18a which leads to a cylindrical portion 18b. The cylindrical portion 18b, in turn, is connected to a cylindrical portion l8cby the tapered portion 18d. The tip of the conical portion 180 may be provided with an insert 50 of hardened material, such as sintered tungsten carbide or alloyed steel.

To connect the percussion bit 18 to the actuator so that the bit 18 will be capable of independent rotation and lateral movement relative to the actuator, at least one ball-and-socket joint is provided. The ball may be formed at the free end of the actuated element of the actuator, while the socket is formed in the percussion bit 18. The joint may be recessed in a preferred manner as illustrated in FIG. 1 in order to secure a more desirable degree of stability in operation for the percussion bit 18. In the preferred manner, the joint is located at the center of rotation of the percussion bit and guide tube system, associated with a center of lateral percussion located at the tip of the percussion bit.

The socket is preferably formed at the closed end of a central bore 52 formed in the portion 18d of the bit 18. The inner surface forming the bore 52 preferably terminates in a concave surface 54. immediately above the surface 54 the bore 52 is provided with threads 56 for securing a socket ring 58. The socket ring 58 is pro vided with a curved surface 60 which forms a conformable continuation of the surface 54 when the ring 58 is fully engaged within the bore 52 so that the surfaces 54 and 60 are contiguous. Preferably, the surfaces 54 and 60 are lined with a shockabsorbing material 62.

As a preferred alternative to connecting the percussion bit 18 directly to the actuator. there is provided according to the present invention. an articulated link 64 which serves along with the percussion bit 18 and the actuator to form at each of its ends a ball'and-socket joint. At its actuator end, the articulated link 64 is joined within the socket formed in an adapter block 66, made integral with or connected to the reciprocated actuated element of the actuator. Preferably, the articulated link is utilized with a recessed socket in the percussion bit 18.

The percussion bit assembly 12 thus described is adaptable for use with any actuator known in the art in addition to the actuator shown and described hereinafter according to the present invention. It can be seen that the percussion bit assembly 12 is relatively inexpensive to fabricate primarily in view of the fact that conventional pneumatic tires can be utilized as part of the spring system. Moreover, the percussion bit assembly 12 is significantly improved from the standpoint of the impact energy which can be safely delivered by the percussion bit 18. Even if the percussion bit 18 strikes an uneven surface and is caused to pivot as a result the spring system will withstand the imposed lateral loads and prevent damage to the hammer. Likewise, if the percussion bit 18 fails to strike the intended working surface or if it strikes the working surface of an object which does not offer the expected resistance, that is, it permits relatively free entry, the hammer is protected by the braking system and spring system; the brake system transmitting an axial loading to the spring system which is, in turn, reacted over a large reactive area.

It should be noted that the brake system is optional, that is, if the percussion bit assembly 12 is intended for use with an actuator which already has a shockabsorbing system, then the brake system can be dispensed with.

Turning now to the actuator assembly 14 to which the percussion bit assembly 12 is operatively connected, there is included a housing member 68 within which a working cylinder 70 is displaceably mounted. Mounted within the working cylinder 70 for reciprocating movement is a piston assembly 72, which comprises the actuated element referred to above. The piston assembly 72 includes a piston 74 and a piston rod 76 which extends through a transverse end plate 78 of the housing member 68. The housing member 68 is connected to the transverse end plate 78 in any conventional manner, such as, for example, by welding. The piston rod 76 extends through a bore 80 formed centrally within the end plate 78. Preferably, the bore 80 is lined with a bushing 82 which is retained within the bore 80 by an externally fastened retaining ring 84. At the opposite end of the bore 80 adjacent to the bushing 82 there is provided a fluid seal 86. The external end of the piston rod 76 can either form the ball of a balland-socket joint, as described above, or it can terminate in an adapter block 66 for receiving one end of the articulated link 64. In this way, the reciprocating output of the actuator is transmitted to the percussion bit l8 of the percussion bit assembly l2.

The housing member 68 is preferably formed to include an upper portion 88 and a lower portion 90. The two portions may be joined together by, for example, a plurality of circumferentially arranged bolted joints 92. Alternatively, the lower portion 90 may be formed integrally with the upper portion 88 if so desired. The free end of the upper portion 88 is closed by a transverse head plate 94.

The working cylinder 70 is closed at one end by a transverse end plate 96 and retained opened at its opposite end. The open end of the working cylinder 70 engages a face seal 98 located within the inner transverse surface of the end plate 78. The free end of the working cylinder 70, whendisplaced within the housing member 68 away from the face seal 98, defines an annular passage 100. The importance of the passage 100 will be described hereinafter.

The assembled members of the actuator described above form a number of working chambers, which, for convenience, will be identified as the first, second, third and fourth working chambers. The first working chamber 102 is defined by the upper portion 88 of the housing member 68, the transverse head plate 94 and the transverse end plate 96. The second working chamber 104 is defined by the lower portion 90 of the housing member 68 and the working cylinder 70. The third working chamber 106 is defined by the working cylinder 70, the transverse end plate 96 and the piston 74. Finally, the fourth working chamber 108 is defined by the working cylinder 70, the piston 74, the piston rod 76 and the transverse end plate 78. As can be seen, the annular passage 100 provides access between the second and fourth working chambers 104 and 108.

The transverse end plate 96, as well as the piston 74, is provided with appropriate seals 110 and 112, respectively, to ensure a sufficient pressure seal between the first and second working chambers 102 and 104, and between the third and fourth working chambers 106 and 108.

To provide a high energy reciprocating output through the piston rod 76, it is desirable according to the present invention to provide rapid escape of the piston cocking liquid during piston firing. To accomplish this purpose, it is proposed, according to the present invention, to provide a large annular passage in the form of the passage 100. With such a design it is possible to minimize the power wasted in forcing liquid from the path of piston during firing. It is only necessary to displace the working cylinder 70 from the face seal 98 at an appropriate time in the cycle of operation of the piston assembly 12.

To accomplish this purpose, the following control circuit is employed. A control unit 114 sequentially controls the operation of a pump 116 and a return valve 120. The pump 116 is connected to the first, second and fourth working chambers 102, 104 and 108, and to a reservoir 118. Ports 122, 128 and 132 in the transverse head plate 94, in the end plate 78, and in the lower portion 90 of the housing member 68, respectively, are provided for this purpose. Finally, the return valve 120 is connected between the first working chamber 102 and the second working chamber 104. Ports 130 and 124 in the transverse head plate 94 and the lower portion 90 of the housing member 68 are provided for this purpose. According to the present invention, the third working chamber 106 is initially supplied with a closed volume of compressed gas through a conventional gas fill port 126 provided in the piston assembly 72. Also, according to the present invention. the working chamber 104 serves as a liquid sump.

MODE OF OPERATION The actuator assembly 14 operates as follows: After pressurizing the third working chamber 106 through the gas fill port 126 in the piston assembly 72, pump 116 is actuated and delivers pressurized liquid from the reservoir 118 to the first working chamber 102 through the port 122. Charging of the first working chamber 102 causes the working cylinder to move in a first direction toward and seat itself against the face seal 98. Thereafter, the pump 116 is caused to deliver pressurized liquid from the reservoir 118 through the port 128 to the fourth working chamber 108. Charging of the fourth working chamber 108 results in moving the piston assembly 72 in a second direction (cocking of the piston assembly), which in turn results in further compressing the gas within the third working chamber 106. After the piston assembly 72 is cocked, the return valve 120 is opened by the control unit 114 permitting a bleed-off from the first working chamber 102 through the port 130 and into the sump 104 through the port 124. As a result of the bleed-off, the working cylinder 70 is moved in the second direction away from the face seal 98 and defines an annular passage which provides access between the fourth working chamber 108 and the sump 104. The pressurized gas in the third working chamber 106 then fires the piston assembly 72 (piston assembly moves in the first direction), thereby actuating the percussion bit 18. Because of the large annular passage 100, the pressurized liquid within the fourth chamber 108 is provided with a means for rapidly escaping into the sump 104 and from there through the port 132 to the reservoir 118 under the influence of the pump 116. Thereafter, the first working chamber 102 is once again charged by the pump 116 causing the working cylinder 70 to be seated against the face seal 98, and the cycle repeated. It should be noted that the working chamber 102 is subsequently charged preferably near the end of the stroke of the piston assembly 72 to effect dampening of the piston stroke.

Because of the principle of a movable working cylinder according to the present invention, it is possible to realize higher energy outputs than has been known heretofore.

Turning now to FIG. 3, there is illustrated an alternative embodiment of the control circuit for effecting operation of the actuator assembly 14. According to this embodiment, a control sensor 134 is mounted in the wall of the working cylinder 70 and is connected to the return valve 120. A slot 136 in the upper portion 88 of the housing member 68 is provided to allow for the movement of the working cylinder 70. At a predetermined point in the cocking of the piston assembly 72, the piston 74 coacts with the control sensor 134 to acmate the return valve 120. Actuation of the return valve 120 causes a bleed-off from the first working chamber 102 with an effect described above. The operation of the pump 116 is similar to that described above. Because of the control sensor 134 it is possible to dispense with the control unit 114 and provide continuous operation of the pump 116 without adversely affecting the high energy output of the actuator assembly 14.

That which is claimed is:

1. In an assembly for mechanical impulse actuators having actuating means, the assembly comprising:

A. a tubular housing;

B. means for connecting said housing to a desired actuator;

C. a percussion bit;

D. means for connecting said percussion bit to the actuating means of the desired actuator. and

E. means supporting said percussion bit for rotational, lateral and axial displacement relative to said housing, said supporting means including:

a. guide means axially guiding said percussion bit during its axial displacement, said guide means being fabricated as a tubular structue which is arranged concentrically between said housing and said percussion bit;

b. spring means; and

c. means mounting said spring means between said guide means and said housing, said spring means exerting, as a result of said mounting means, both axial and lateral reactive forces in response to the axial and lateral displacements of said percussion bit, with said axial reactive force being exerted through said mounting means.

2. The assembly as defined in claim 1, wherein said spring means include a plurality of toroidal members forming part of said concentric arrangement, with each of said plurality of toroidal members being spaced from each other in the axial direction of displacement of said percussion bit by said mounting means.

3. The assembly as defined in claim 2, wherein said mounting means include a plurality of annular members, with a first portion thereof forming with said guide means a plurality of first recesses for said toroidal members and a second portion thereof forming with the housing an equal plurality of second recesses for said toroidal members, said first and second recesses forming corresponding and concentric pairs of recesses in the axial direction of displacement of said percussion bit.

4. The assembly as defined in claim 2, wherein each of said plurality of toroidal members is a pneumatic tire.

5. The assembly as defined in claim 1, wherein said means for connecting said percussion bit to the actuating means includes a ball-and-socket joint with said socket being formed in said percussion bit by a concavely curved surface thereof, and a removable ring means having a curved surface which when rendered contiguous with said concavely curved surface forms a conformable continuation thereof.

6. The assembly as defined in claim 5, wherein said percussion bit includes a bore which penetrates into said percussion bit from one end thereof and in the axial direction of displacement thereof and forms a closed end, said ball-and-socket being formed at said closed end.

7. The assembly as defined in claim 5, wherein said joint is located at the center of rotation of the assembly of said percussion bit and said supporting means which is associated with the center of percussion at the tip of said percussion bit.

8. The assembly as defined in claim 1, wherein said means for connecting said percussion bit to the actuating means includes a link element forming a ball-andsocket joint at one end thereof with said percussion bit and having a spherical surface at the other end thereof for forming a ball-and-socket joint with the actuating means, said sockets being formed in the percussion bit and the actuating means, respectively, by a concavely curved surface and removable ring means in each, with each said ring means having a curved surface which, when rendered contiguous with its respective concavely curved surface, forms a conformable continuation thereof.

9. The assembly as defined in claim 1, further comprising brake means mounted to directly engage said percussion bit in order to decelerate the axial movement of said percussion bit and thereby limit the stroke of the actuating means.

10. The assembly as defined in claim 9, wherein said brake means is mounted to the inner surface of said 5 guide means, and wherein said percussion bit is provided with a tapered outer surface portion which engages said brake means after a predetermined axial displacement of said percussion bit.

11. The assembly as defined in claim 1, wherein said to guide means is displaceable in the axial direction of displacement of said percussion bit, said assembly further comprising: brake means mounted to said guide means to directly engage said percussion bit thereby effecting the axial displacement of said guide means in the course of the axial displacement of said guide means in the course of the axial displacement of said percussion bit; and brake means mounted to said spring means to directly engage said housing, both said engagements serving to decelerate the axial movement of said percussion bit and thereby limit the stroke of the actuating means.

12. The assembly as defined in claim ll, wherein said guide means includes a tapered portion of the inside surface of which said brake means is mounted, and

wherein said percussion bit includes a tapered portion which engages said guide means mounted brake means to effect the axial displacement of said guide means.

13. The assembly as defined in claim 11, wherein said percussion bit includes means for retracting said guide means after its axial displacement.

14. in combination, a percussion bit and link for connecting said percussion bit to the actuating means of a mechanical impulse actuator so that said percussion bit can be axially driven by the actuating means and laterally displaced relative to the actuating means and said link means, the percussion bit comprising:

A. a work engaging tip portion;

B. a brake means engaging portion;

C. an intermediate portion which joins said tip portion and said brake means engaging portion to form thereby a continuous bit; and

D. an actuating ring extending generally radially outwardly from said intermediate portion.

15. A mechanically actuated hammer, comprising in combination:

A. a mechanical impulse actuator having actuating means; B. a percussion bit assembly including a percussion bit;

C. means connecting said percussion bit assembly to said actuator; and

D. means connecting said percussion bit to said actuating means, said mechanical impulse actuator including:

a. a housing member;

b. a cylinder displaceably mounted within said housing member;

c. a piston assembly forming said actuating means,

said piston assembly being mounted to said housing member for reciprocal movement within said cylinder, said piston assembly including a piston and a piston rod, said piston rod being mounted to said housing member to extend outwardly therefrom to thereby serve as the reciprocating output;

d. first means effecting movement of said cylinder relative to said housing member and said piston assembly in a first direction toward said piston assembly;

e. second means effecting movement of said piston assembly relative to said cylinder and said housing member in a second direction opposite to said first direction; and

f. third means effecting movement of said cylinder and said piston assembly relative to each other and to said housing member, so that said cylinder means moves in said second direction while said piston assembly moves in said first direction said first, second and third means being associated in their respective operations to produce the reciprocating output.

16. A mechanically actuated hammer, comprising in combination:

A. a mechanical impulse actuator having actuating means;

8. percussion bit assembly including a percussion bit;

C. means connecting said percussion bit assembly to said actuator; and

D. means connecting said percussion bit to said actuating means, said percussion bit assembly including:

a. a tubular housing, said housing being connected to said actuator by said means (C);

b. guide means axially guiding said percussion bit, said guide means being fabricated as a tubular structure which is arranged concentrically between said housing and said percussion bit;

c. spring means; and

d. means mounting said spring means between said guide means and said housing, said spring means exerting, as a result of said mounting means, both axial and lateral reactive forces in response to axial and lateral displacements of said percussion bit, with said axial reactive forces being exerted through said mounting means.

17. The mechanically actuated hammer as defined in claim 16, wherein said housing and said guide means are fabricated as tubular structures which are concentrically arranged with each other and said percussion bit, and wherein said spring means include a plurality of toroidal members forming part of said concentric arrangement, with each of said plurality of toroidal members being spaced from each other in the axial direction of displacement of said percussion bit by said mounting means.

18. The mechanically actuated hammer as defined in claim 17, wherein each of said plurality of toroidal members is a pneumatic tire.

19. The mechanically actuated hammer as defined in claim 16, wherein said means (D) comprises link means which forms an articulated joint at its connection with both said actuating means and said percussion bit.

20. The mechanically actuated hammer as defined in claim 16, wherein said percussion bit assembly further includes brake means mounted to directly engage said percussion bit in order to decelerate the axial movement of said percussion bit and thereby limit the stroke of said actuating means.

21. The mechanically actuated hammer as defined in claim 16, wherein said mechanical impulse actuator further includes a displaceable cylinder within which said actuating means is reciprocated, and means for effecting displacement of both said cylinder and said actuating means.

22. The mechanically actuated hammer as defined in claim 21, wherein said mechanical impulse actuator further includes:

a. a housing member within which said cylinder is displaceably mounted, said means (C) connecting said percussion bit assembly to said housing member;

b. first means effecting movement of said cylinder relative to said housing member and said piston assembly;

c. second means effecting movement of said piston assembly relative to said cylinder and said housing member; and

d. third means effecting movement of said cylinder and said piston assembly relative to each other and to said housing member, said first, second and third means being associated in their respective operations to produce a reciprocating movement of said actuating means. 

1. In an assembly for mechanical impulse actuators having actuating means, the assembly comprising: A. a tubular housing; B. means for connecting said hoUsing to a desired actuator; C. a percussion bit; D. means for connecting said percussion bit to the actuating means of the desired actuator; and E. means supporting said percussion bit for rotational, lateral and axial displacement relative to said housing, said supporting means including: a. guide means axially guiding said percussion bit during its axial displacement, said guide means being fabricated as a tubular structue which is arranged concentrically between said housing and said percussion bit; b. spring means; and c. means mounting said spring means between said guide means and said housing, said spring means exerting, as a result of said mounting means, both axial and lateral reactive forces in response to the axial and lateral displacements of said percussion bit, with said axial reactive force being exerted through said mounting means.
 2. The assembly as defined in claim 1, wherein said spring means include a plurality of toroidal members forming part of said concentric arrangement, with each of said plurality of toroidal members being spaced from each other in the axial direction of displacement of said percussion bit by said mounting means.
 3. The assembly as defined in claim 2, wherein said mounting means include a plurality of annular members, with a first portion thereof forming with said guide means a plurality of first recesses for said toroidal members and a second portion thereof forming with the housing an equal plurality of second recesses for said toroidal members, said first and second recesses forming corresponding and concentric pairs of recesses in the axial direction of displacement of said percussion bit.
 4. The assembly as defined in claim 2, wherein each of said plurality of toroidal members is a pneumatic tire.
 5. The assembly as defined in claim 1, wherein said means for connecting said percussion bit to the actuating means includes a ball-and-socket joint with said socket being formed in said percussion bit by a concavely curved surface thereof, and a removable ring means having a curved surface which when rendered contiguous with said concavely curved surface forms a conformable continuation thereof.
 6. The assembly as defined in claim 5, wherein said percussion bit includes a bore which penetrates into said percussion bit from one end thereof and in the axial direction of displacement thereof and forms a closed end, said ball-and-socket being formed at said closed end.
 7. The assembly as defined in claim 5, wherein said joint is located at the center of rotation of the assembly of said percussion bit and said supporting means which is associated with the center of percussion at the tip of said percussion bit.
 8. The assembly as defined in claim 1, wherein said means for connecting said percussion bit to the actuating means includes a link element forming a ball-and-socket joint at one end thereof with said percussion bit and having a spherical surface at the other end thereof for forming a ball-and-socket joint with the actuating means, said sockets being formed in the percussion bit and the actuating means, respectively, by a concavely curved surface and removable ring means in each, with each said ring means having a curved surface which, when rendered contiguous with its respective concavely curved surface, forms a conformable continuation thereof.
 9. The assembly as defined in claim 1, further comprising brake means mounted to directly engage said percussion bit in order to decelerate the axial movement of said percussion bit and thereby limit the stroke of the actuating means.
 10. The assembly as defined in claim 9, wherein said brake means is mounted to the inner surface of said guide means, and wherein said percussion bit is provided with a tapered outer surface portion which engages said brake means after a predetermined axial displacement of said percussion bit.
 11. The assembly as defined in claim 1, wherein said guide means is displaceable in the axial diRection of displacement of said percussion bit, said assembly further comprising: brake means mounted to said guide means to directly engage said percussion bit thereby effecting the axial displacement of said guide means in the course of the axial displacement of said guide means in the course of the axial displacement of said percussion bit; and brake means mounted to said spring means to directly engage said housing, both said engagements serving to decelerate the axial movement of said percussion bit and thereby limit the stroke of the actuating means.
 12. The assembly as defined in claim 11, wherein said guide means includes a tapered portion of the inside surface of which said brake means is mounted, and wherein said percussion bit includes a tapered portion which engages said guide means mounted brake means to effect the axial displacement of said guide means.
 13. The assembly as defined in claim 11, wherein said percussion bit includes means for retracting said guide means after its axial displacement.
 14. In combination, a percussion bit and link for connecting said percussion bit to the actuating means of a mechanical impulse actuator so that said percussion bit can be axially driven by the actuating means and laterally displaced relative to the actuating means and said link means, the percussion bit comprising: A. a work engaging tip portion; B. a brake means engaging portion; C. an intermediate portion which joins said tip portion and said brake means engaging portion to form thereby a continuous bit; and D. an actuating ring extending generally radially outwardly from said intermediate portion.
 15. A mechanically actuated hammer, comprising in combination: A. a mechanical impulse actuator having actuating means; B. a percussion bit assembly including a percussion bit; C. means connecting said percussion bit assembly to said actuator; and D. means connecting said percussion bit to said actuating means, said mechanical impulse actuator including: a. a housing member; b. a cylinder displaceably mounted within said housing member; c. a piston assembly forming said actuating means, said piston assembly being mounted to said housing member for reciprocal movement within said cylinder, said piston assembly including a piston and a piston rod, said piston rod being mounted to said housing member to extend outwardly therefrom to thereby serve as the reciprocating output; d. first means effecting movement of said cylinder relative to said housing member and said piston assembly in a first direction toward said piston assembly; e. second means effecting movement of said piston assembly relative to said cylinder and said housing member in a second direction opposite to said first direction; and f. third means effecting movement of said cylinder and said piston assembly relative to each other and to said housing member, so that said cylinder means moves in said second direction while said piston assembly moves in said first direction said first, second and third means being associated in their respective operations to produce the reciprocating output.
 16. A mechanically actuated hammer, comprising in combination: A. a mechanical impulse actuator having actuating means; B. percussion bit assembly including a percussion bit; C. means connecting said percussion bit assembly to said actuator; and D. means connecting said percussion bit to said actuating means, said percussion bit assembly including: a. a tubular housing, said housing being connected to said actuator by said means (C); b. guide means axially guiding said percussion bit, said guide means being fabricated as a tubular structure which is arranged concentrically between said housing and said percussion bit; c. spring means; and d. means mounting said spring means between said guide means and said housing, said spring means exerting, as a result of said mounting Means, both axial and lateral reactive forces in response to axial and lateral displacements of said percussion bit, with said axial reactive forces being exerted through said mounting means.
 17. The mechanically actuated hammer as defined in claim 16, wherein said housing and said guide means are fabricated as tubular structures which are concentrically arranged with each other and said percussion bit, and wherein said spring means include a plurality of toroidal members forming part of said concentric arrangement, with each of said plurality of toroidal members being spaced from each other in the axial direction of displacement of said percussion bit by said mounting means.
 18. The mechanically actuated hammer as defined in claim 17, wherein each of said plurality of toroidal members is a pneumatic tire.
 19. The mechanically actuated hammer as defined in claim 16, wherein said means (D) comprises link means which forms an articulated joint at its connection with both said actuating means and said percussion bit.
 20. The mechanically actuated hammer as defined in claim 16, wherein said percussion bit assembly further includes brake means mounted to directly engage said percussion bit in order to decelerate the axial movement of said percussion bit and thereby limit the stroke of said actuating means.
 21. The mechanically actuated hammer as defined in claim 16, wherein said mechanical impulse actuator further includes a displaceable cylinder within which said actuating means is reciprocated, and means for effecting displacement of both said cylinder and said actuating means.
 22. The mechanically actuated hammer as defined in claim 21, wherein said mechanical impulse actuator further includes: a. a housing member within which said cylinder is displaceably mounted, said means (C) connecting said percussion bit assembly to said housing member; b. first means effecting movement of said cylinder relative to said housing member and said piston assembly; c. second means effecting movement of said piston assembly relative to said cylinder and said housing member; and d. third means effecting movement of said cylinder and said piston assembly relative to each other and to said housing member, said first, second and third means being associated in their respective operations to produce a reciprocating movement of said actuating means. 